This section is from the book "Commercial Gardening Vol2", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
This tuberous-rooted Peruvian perennial is usually treated as a half-hardy annual. It grows 2-4 ft.-high, and has large, smooth, oval, pointed leaves, and late in summer masses, of long-tubed funnel-shaped flowers, red, white, or yellow in colour, some being blotched or striped with other shades. Other species are longiflora, white, pink, or violet, with long tubes; and multifiora, bright purple. There are also varieties having variegated leaves, and a dwarf or Tom Thumb strain.